Generally, in a roof panel of a vehicle, as illustrated in FIG. 1, a headlining (L) is installed at an indoor side thereof to provide a buffer function, mood or the like, as illustrated in FIG. 2. The headlining (L) is fixed to a side roof rail by a clip, and formed of various materials such as vinyl and cotton, and serves as an insulating material against a temperature change from an outside. The headlining (L) is manufactured by various methods and of various materials, as described in the following patent documents 1 to 3.
The patent document 1 discloses a manufacturing method of the headlining, which is capable of strengthening an adhesive force of each layer of an acoustic head lining, while simplifying a manufacturing process thereof, and improving reliability of a product, and also preventing a thermal deformation of polyurethane foam, and thus providing excellent acoustic absorption performance.
The patent document 2 discloses a material of a headlining for a vehicle, which includes a first layer including natural fiber, polypropylene and polyethylene terephthalate, a second layer including thermoplastic (TF) foam, and a third layer including the natural fiber, the polypropylene and the polyethylene terephthalate, and is capable of realizing high acoustic absorption performance, environment friendliness and a light weight, and a manufacturing method thereof.
The patent document 3 discloses a manufacturing method of the headlining, which is capable of providing an excellent adhesive force by using adhesive powder having a graft polymer property, being manufactured in a simple process without using an adhesive film, compared with a conventional manufacturing method using the adhesive film and adhesive powder, reducing a manufacturing cost, improving inconvenience in using the adhesive film, and also providing an acoustic absorption effect in the vehicle by forming a permeable adhesive layer.
However, the conventional headlining has the following problems:
(1) The conventional headlining does not include a material which may shield or prevent heat of sunlight from being introduced into an inside of a vehicle through a roof panel in summertime.
(2) This causes an internal temperature of the vehicle to be rapidly increased, as the direct sunlight is applied to the roof panel in the summertime.
(3) Like this, when the internal temperature of the vehicle is increased, and a child or the old and the infirm stays for a long stretch of time, a safety accident, such as heat exhaustion and heatstroke, which can be prevented in advance may be caused.
(4) Also, when a canned drink or a lighter using gas as fuel is exposed in the hot inside of the vehicle for a long period of time, the drink or the lighter may explode and may cause a fire or damage to a driver or a passenger.
(5) When an air conditioner is operated in a state in which the roof panel is exposed to the sunlight for long time, heated air should be cooled, and energy consumption is increased, and thus fuel efficiency is reduced.